This is a proposal for continuing studies of neurogenic hypertension in the rat induced by sinoaortic denervation, SAD. Major objectives are to delineate plasma and tissue indices that reflect the state of sympathetic nervous activity and to determine what processes develop in the course of time to alter these indices. Specific studies will: 1) test the hypothesis that degradative enzyme activity and catecholamine metabolites increase in tissues and blood in the course of SAD hypertension and, 2) estimate degree of participation of the renin-angiotensin system. Additional aims are: 1) to identify biochemical changes in specific brain cells of SAD rats and 2) to determine the course, distribution and specific location of nerve terminals from baroreceptor afferents in the nucleus tractus solitarius. Continuing studies will include: 1) effects of dietary sodium and adrenalectomy on the course of neurogenic hypertension and associated plasma indices, 2) investigations of a centrally located baroreceptor reflex mechanism unmasked by SAD and, 3) comparative studies of female SHR and female SAD rats.